This invention relates to gas meters, and in particular, to means for preventing fraudulent use thereof or "gas theft".
With the rising costs for the use of gas, as well as other energy sources, gas theft has become much more prevalent. Public utilities are losing significant amounts of revenue due to gas theft and in turn are attempting to recover these losses by raising the unit cost. With conventional gas meters it is surprisingly easy to perpetrate gas theft: the meter only needs to be removed and then temporarily reinstalled oppositely. The reverse gas flow through the meter causes the indicating mechanism to run in reverse showing an apparent negative gas consumption. After a predetermined period of time, the meter is reinstalled properly such that, when subsequently read, the indicating mechanism will show a total gas consumption considerably less than the actual consumption.
U.S. Pat. No. 764,605 of Lambert discloses a meter having an indexing device therein which causes the indicator to always run in a forward direction regardless of the actual direction of flow of the metered medium. However, the indexing device takes the form of a cam-actuated slide in which factors such as inertia and friction adversely affect the wear thereof.